The target that no patient should wait more than 18 weeks from seeing their GP to completing hospital treatment may be redefined.

The shift was needed to make allowance for people who chose to wait longer, did not turn up for their appointments or who had clinical reasons to postpone treatment, said Ben Bradshaw, the health minister, on Thursday.

One option under consideration was to set the target so that 90 per cent of patients who needed hospital admission were treated within 18 weeks. For those treated as outpatients or in the community the target would be 95 per cent.

The shift is likely to be seen by some as an attempt to soften a demanding target that the National Health Service is required to hit by the end of next year. But Mr Bradshaw said the change was aimed at recognising reality, without burdening hospitals with the bureaucracy of having routinely to provide reasons for every patient who appeared to breach the 18-week promise.

“Some patients will want to put their treatment off, perhaps because they want to go on holiday,” he said. Others might fail to keep appointments. In some cases there would be good clinical reasons for patients waiting longer.

The Department of Health estimated that 10 per cent of patients fell into these categories, he said. It was now “looking for the right line” to draw to provide a measure of success “without putting an overbureaucratic burden on trusts”.

The parallel was with the four-hour wait for treatment in accident and emergency departments where the target was 98 per cent in recognition that some patients needed to wait longer for clinical observation.

Norman Lamb, the Liberal Democrat health spokesman, said ministers would struggle to convince the public “that this change isn’t merely providing political cover because of fears they will fail to achieve their ­target”.

But Mr Bradshaw said: “The real test of success will be patient experience. They will know whether they have had to wait unnecessarily, and the Healthcare Commission [the NHS inspectorate] will be looking at this with eagle eyes.”

His comments were made as the department published its latest, but still incomplete, data on 18-week waits, which show continued progress towards the target but with large variations around the country.

Fifty-six per cent of patients admitted to hospital were seen within 18 weeks in August, up from 48 per cent in March, along with three-quarters whose treatment did not require admission.